biconvex

/baɪˈkɑnvɛks/
adjective
  1. Curved outward on both sides, like a typical magnifying lens.
    • A biconvex lens is used in a magnifying glass to make objects look larger.
    • The eyeglasses had biconvex lenses to help the patient see things up close.
    • In the lab, we used a biconvex lens to focus sunlight onto a piece of paper.